000 AXPZ20 KNHC 050403 TWDEP Tropical Weather Discussion NWS National Hurricane Center Miami FL 0136 UTC Thu Jan 5 2017 Tropical Weather Discussion for the eastern Pacific Ocean from the Equator to 32N, east of 140W. The following information is based on satellite imagery, weather observations, radar, and meteorological analysis. Based on 0000 UTC surface analysis and satellite imagery through 0330 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... The monsoon trough axis extends from 05N77W to 04N80W to 06N97W. The intertropical convergence zone axis extends from 06N97W to 07N110W to 10N135W to 09N140W. Scattered moderate convection is within 45 to 60 NM of the ITCZ between 102W and 105W. ...DISCUSSION... OFFSHORE WATERS WITHIN 250 NM OF MEXICO... A weak 1019 mb high pressure is centered west of Baja California Norte near 27N121W, and is helping to produce gentle to moderate northerly winds across the Pacific waters off the coast of Baja California tonight. Seas in the 3 of 5 FT range prevail over this area. The pressure gradient will tighten slightly offshore of Baja California Sur through the end of the week, allowing for northwest flow to increase to moderate to fresh, then diminishing this weekend as the gradient relaxes to the west of the peninsula. In the Gulf of California, a locally tight pressure gradient is supporting fresh northwest winds of 20 KT flow from 23N to 28N as measured by an earlier 1730 UTC ASCAT scatterometer pass. Seas are 4 to 6 FT in the area S of 27N. The gradient will relax in the gulf late tonight, then will tighten more significantly this weekend with northwest flow increasing to fresh to strong south of 27N, which will build seas to 5 to 7 FT. In the Gulf of Tehuantepec, northerly winds will continue to pulse to fresh to strong mainly during the overnight into the early morning hours into early Thursday, with seas up to 7 FT. Light southerly flow will then prevail late Thursday through Friday evening with seas of 2 to 3 FT. A strong cold front will move through the Gulf of Mexico to the north of the area Friday through Saturday. Winds will become northerly and rapidly increase to 20 to 30 kt in the Gulf of Tehuantepec by Saturday morning, then increasing to gale force by Saturday aFTernoon. Model guidance continues to indicate winds increasing to storm force by early Sunday morning, continuing into Monday. The potential exists for the strongest gap wind thus far this cold season in the area. Wave model guidance propagates a very large area of high seas well away from the source region, with significant wave heights in the Tehuantepec area building to 23 to 25 FT by Sunday night. Elsewhere between Cabo Corrientes and the Tehuantepec region, light to gentle breezes and seas in the 3 to 5 FT range, primarily in northwest swell, will prevail over the next several days. OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR... In the Gulf of Papagayo, winds will pulse to fresh to locally strong during the overnight into the early morning hours Thursday, then to moderate to fresh thereafter through early Saturday. Offshore flow will then increase back to fresh to strong Saturday night, with winds approaching near gale force by late Sunday into Monday as strong high pressure ridges southward across interior Central America in the wake of the Gulf of Mexico/Caribbean cold front. In the Gulf of Panama, nocturnal northerly flow will continue to pulse to fresh during the next few nights, increasing to fresh to strong early next week due to the strong high pressure ridging. These gap winds, along with a possible storm force event in the Gulf of Tehuantepec, will generate a very large area of high seas that will eventually extend from Tehuantepec to Papagayo to just northwest of the Galapagos Islands, spreading westward to 110W by early Tuesday. Elsewhere, light to moderate south to southwest winds will prevail south of the monsoon trough region, with seas 5 FT or less through the end of the week and the upcoming weekend. REMAINDER OF THE AREA... A weak to modest pressure gradient prevails elsewhere over the forecast waters. Fresh trade winds prevail south of the high between 118W and 135W, between the ITCZ and about 15N. Combined seas are generally running between 6 to 9 FT across this zone. Across the far northwest waters, a weak surface trough extends from 29N133W to 22N137W. A weak cold front has entered the far NW portion of the area and currently extends from 30N137W to 27N140W. An area of 8 to 11 FT seas in mixed southeast and northwest swell is present across this area between the surface trough and cold front. The cold front will gradually dissipate with a remnant boundary found from 30N135W to 26N140W by 24 to 36 hours. Even with the features dissipating, associated mainly northwest swell of 8 to 11 FT will continue to propagate to the south and southeast, gradually mixing with the fresh trade wind seas to the south through the end of the week. The next frontal system and associated increasing winds and seas may approach the far northwest portion of the discussion area by late Saturday. $$ COBB